Apparatus for detecting low liquid level in bottom-draining container

ABSTRACT

An apparatus for is disclosed for detecting low liquid level in a bottom-draining container (12), the apparatus including a spout (14, 48) extended outwardly from the container, the spout having a central bore (18) through which liquid can drain from a bottom of the container; at least one guide member (26, 56, 62) positioned in the spout; at least one float (38) mounted for movement in the spout along the guide member, the float being buoyant in a liquid to be drained from the container; a source (42) for directing a beam of radiation into the spout along a path intersected by the float when a liquid drains to a preselected level within the spout; and a device (44, 46) for detecting when the float intersects the beam. The guide member may be omitted in one embodiment.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of CPA U.S. Ser. No. 08/671,459 filed Jun. 27,1996, now U.S. Pat. No. 6,012,606.

TECHNICAL FIELD

The invention relates to containers for dispensing liquids. Moreparticularly, the invention concerns containers which drain through abottom opening and techniques for detecting a low liquid level in suchcontainers.

BACKGROUND OF THE INVENTION

Commonly assigned, published European Patent Application No. 0 675 072A1 discloses a valve assemblage useful for dispensing liquids from acollapsible container or a rigid, vented container. At the bottom of thecontainer, a first valve is installed in a spout of the container, thefirst valve including a moveable, spring-biased piston which normallyprevents flow of liquid from the container. An associated apparatus,such as a photographic processor into which the liquid is to bedispensed, includes a second valve having a probe member which engagesthe piston of the first valve to move the piston to a position whichpermits flow. As the first valve is opened by the probe, the secondvalve also opens, thus establishing a flow path for liquid from thecontainer into the associated apparatus.

As the associated apparatus operates, the liquid drains from thecontainer. It would be desirable to provide a simple means for detectingand signaling a low liquid level within the container, to enable anoperator of the associated apparatus to replace the container in atimely fashion. Various systems are known for detecting liquid level ina vessel, such as those shown in U.S. Pat. Nos. 4,014,010 and 4,714,176.However, such systems either require expensive and complex modificationsto the vessel to incorporate the detection system, or measure liquidlevel outside the vessel under circumstances where the vessel mayactually have emptied before low level is detected. In the latter case,air may be drawn into the associated apparatus, which could causeoperating difficulties.

SUMMARY OF THE INVENTION

The primary objective of the invention is to provide an improvedapparatus for detecting low liquid level in a bottom-draining container.

A further objective is to provide such an apparatus which can be usedwith existing container styles without requiring modification of thecontainer.

Another objective is to provide such an apparatus which can be used withan associated apparatus which uses liquid from the container, withoutrequiring substantial modifications of the associated apparatus.

Yet another objective is to provide such an apparatus which can detectlow liquid level in time to prevent air from entering an associatedapparatus from the container.

These objectives are given only by way of illustrative examples; thusother desirable objectives and advantages inherently achieved by thedisclosed invention may occur or become apparent to those skilled in theart. Nonetheless, the scope of the invention is to be limited only bythe appended claims.

An apparatus in accordance with the invention is useful for detectinglow liquid level in a bottom-draining container. As such, the apparatusmay include a spout extended outwardly from the container, the spouthaving a central bore through which liquid can drain from a bottom ofthe container; at least one guide member positioned in the spout; atleast one float mounted for movement in the spout along the guidemember, the float being buoyant in a liquid to be drained from thecontainer; means for directing a beam of radiation into the spout alonga path intersected by the float when a liquid drains to a preselectedlevel within the spout; and means for detecting when the floatintersects the beam. The guide member may be omitted in one embodiment.

The apparatus may include a closure member for the spout, the guidemember being supported by the closure member; and means supported by theclosure member for allowing liquid to be drained from the container. Themeans for allowing liquid to be drained may include a valve supported bythe closure member, the valve including a body member constituting theguide member. When the valve body is cylindrical, the float may beannular and may extend around the valve body, the valve body havingradial stop means for limiting upward movement of the float. The spoutand valve may be translucent to- and the float may be opaque to the beamof radiation. Alternatively, the spout may be translucent to- and thefloat may be reflective of the beam of radiation.

In another embodiment, the means for allowing liquid to be drained mayinclude a drain conduit supported by the closure member, the guidemember being positioned within the spout adjacent the drain conduit.There may be a plurality of guide members arranged around an entrance tothe drain conduit, the float may be annular and may extend around theplurality of guide members, and the guide members may include radialstop means for limiting upward movement of the float.

In yet another embodiment, the means for allowing liquid to be drainedmay include a frangible portion or a pierceable septum portion of theclosure member, the guide member being positioned within the spoutadjacent the frangible or septum portion. There may be a plurality ofguide members arranged around the frangible or septum portion, the floatmay be annular and may extend around the plurality of guide members, andthe guide members may include radial stop means for limiting upwardmovement of the float.

A closure in accordance with the invention is useful for abottom-draining container. The closure may include a first body member;means associated with the first body member for attaching the closure toan associated container; a guide member supported by the first bodymember so that the guide member will extend upward into an associatedcontainer when the closure is attached; means supported by the firstbody member for allowing liquid to be drained from an associatedcontainer; and at least one float mounted for movement along the guidemember, the float being buoyant in a liquid to be drained from anassociated container. The means for allowing liquid to be drained mayinclude a valve supported by the first body member, a drain conduit, afrangible portion, or a pierceable septum portion of the types describedin the preceding paragraphs.

A bottom-draining container in accordance with the invention may includea spout extended outwardly from the container, the spout having acentral bore through which liquid can drain from a bottom of thecontainer; at least one guide member positioned in the spout; and atleast one float mounted for movement in the spout along the guidemember, the float being buoyant in a liquid to be drained from thecontainer. The container also may include a closure member for thespout, the guide member being supported by the closure member; and meanssupported by the closure member for allowing liquid to be drained fromthe container. The means for allowing liquid to be drained may include avalve supported by the first body member, a drain conduit, a frangibleportion, or a pierceable septum portion of the types described in thepreceding paragraphs. The guide member may be omitted in one embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objectives, features and advantages of theinvention will be apparent from the following more particulardescription of the preferred embodiments of the invention, asillustrated in the accompanying drawings.

FIG. 1 is an elevation, centerline section view of one embodiment of theapparatus, closure and container according to the invention, including adispensing valve in the spout from the container.

FIG. 2 is an elevation, centerline section view of a second embodimentof the apparatus, closure and container according to the invention,including a drain conduit through the closure.

FIG. 3 is an elevation, centerline section view of a third embodiment ofthe apparatus, closure and container according to the invention,including a frangible portion or a pierceable portion in the closure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following is a detailed description of the preferred embodiments ofthe invention, reference being made to the drawings in which the samereference numerals identify the same elements of structure in each ofthe several Figures.

Referring to FIG. 1, those skilled in the art will understand a firstembodiment of an apparatus 10 for detecting low liquid level inaccordance with the invention. A container 12, shown only fragmentarily,may be collapsible or rigid and vented. In a suitable opening through abottom of container 12, a spout member 14 is mounted to extend outwardlyof the container. A flange 16, extends radially outwardly from the spoutand is sealed to container 12 in any convenient way, such as by heatsealing. A central bore 18 extends through the spout to facilitatedraining of liquid from the container. At a lower end of bore 18, aradially inwardly and circumferentially extended flange 20 engages acombined valve body and container closure 22. A circumferential groovein closure 22 tightly receives flange 20 to provide a seal. Extendedupwardly from closure 22 is an integrally molded valve cylinder 26within which a hollow valve piston 28 is mounted for sliding movement. Aspring 30 is captured between cylinder 26 and piston 28 to bias thepiston to the illustrated, closed position where a radially outwardlyextended shoulder 32 on the piston engages a radially inwardly extendedshoulder 34 on cylinder 26. A plurality of radial ports 36 extendthrough cylinder 26 near its lower end. In operation of the valve ofFIG. 1, the container is lowered onto a probe in an associatedapparatus. The probe engages piston 28 and causes it to move upwardlywithin cylinder 26 against the force of spring 30. Eventually, ports 36are opened as the piston moves upwardly, thereby permitting flow ofliquid downwardly from container 12 to the associated apparatus.

The invention provides means for detecting when the level of liquidreaches about the middle of spout 14. At least one annular float 38,made to be buoyant in the liquid flowing from the container, is mountedfor sliding movement on an exterior surface of cylinder 26, which thusacts as a guide member for the float. A radially outwardly extended stop40 is provided at or near an upper end of cylinder 26 to limit theupward movement of the float. Although a float which moves on a guidemember has the advantage of capturing the float within the spout, thefloat also could comprise one or more spherical bodies placed in thecontainer at the time of filling with liquid. In that instance, thefloat would simply roll and settle into the spout as the liquid leveldrops, making the guide member unnecessary. Or the float could beconfined in the spout by any suitable means which would not interferewith flow of liquid from the spout.

Outside of spout 14, typically in the associated apparatus, a radiationsource 42 is provided which produces a beam of radiation to which thematerials of spout 14, cylinder 26 and piston 28 are translucent and towhich the material of float 38 is opaque. The beam of radiation isdirected across a chord, preferably a diameter, of spout 14; so that thefloat will intersect the beam as the float falls within the spout whenthe liquid has drained to that level. Opposite to source 42, a radiationdetector 44 is provided. An alarm circuit 46, which may be comprised ina controller for the associated apparatus, is operatively connected tosource 42 and detector 44. Those skilled in the art will appreciate thatsource 42 may be a conventional, combined emitter and detector, in whichcase float 38 would be reflective of the beam and separate detector 44would be unnecessary, without departing from the scope of the invention.Because the liquid level is detected in spout 14, only a smallpercentage of the liquid originally in the container will remain whendetector 44 is actuated. This is important since many governmental unitshave issued environmental regulations which require that less than about3%, typically, of a potentially hazardous liquid remain in the containerat the time of disposal.

When the liquid level is above spout 14, float 38 will rise to itsmaximum height, against stop 40. The beam from source 42 will passthrough the translucent materials of spout 14, cylinder 26 and piston 28to detector 44. As the liquid level drops into the spout, the float ofopaque material will settle downward, eventually interrupting the beamof radiation and causing detector 44 and alarm circuit 46 to alert theoperator of the associated equipment. For a source which produces lighthaving wavelengths in the infrared spectrum, a suitable translucentmaterial is low density polyethylene plastic; and a suitable opaquematerial is carbon-filled high density polyethylene plastic. Thoseskilled in the art will appreciate, however, that other materials andradiation spectrums may be selected without departing from the scope ofour invention.

FIG. 2 shows a second embodiment of the invention. Container 12 includesan integral spout or neck 48 which accepts a screw-on closure 50 in thefamiliar manner. A central drain conduit 52 extends from closure 50 andincludes a conventional hose fitting 54 for attachment to a deliveryhose, not shown, in the associated apparatus. Extended upwardly fromclosure 50 around an entrance to conduit 52 are a plurality of guidemembers 56 which may be molded integrally with the closure. The guidemembers are separated by slots 58, only one of which is visible in thesection view of FIG. 2. Float 38 is mounted around the guide members andits upward movement is limited by radial stops 40 at or near upper endsof the guide members. The second embodiment operates in the same manneras the first.

FIG. 3 shows a third embodiment of the invention. Rather than drainconduit 52, closure 50 includes a central frangible portion 60 which canbe broken by a sharp probe or cannula in the associated apparatus, inthe familiar manner. Rather than a frangible portion, a pierceableseptum may be use. Extended upwardly from closure 50 around portion 60are a plurality of guide members 62 which may be molded integrally withthe closure. The guide members are separated by slots 64, only one ofwhich is visible in the section view of FIG. 3. The third embodimentoperates in the same manner as the first and second.

The invention provides various advantages. The apparatus of FIGS. 1 to 3will reliably and simply detect low liquid level in a bottom-drainingcontainer, without requiring expensive modifications to the container orthe associated apparatus into which the liquid is to be dispensed.Because the detector senses liquid level in the spout of the container,only a tiny percentage of the liquid originally in the container willremain, an amount well below regulatory limits for disposal ofcontainers for potentially hazardous materials. The closure of FIGS. 1to 3 can be made and assembled with a float for later installation intoa spout of a suitable container. Containers with closures embodying theguide members and float in accordance with the invention may be filledand shipped in the same manner as prior art containers.

Parts List

10 . . . apparatus for detecting low liquid level

12 . . . container

14 . . . spout extended outwardly from 12

16 . . . radial flange of 14

18 . . . central bore of 14

20 . . . radially inward flange in 18

22 . . . valve body and container closure

24 . . . circumferential groove in 22

26 . . . upwardly extended valve cylinder

28 . . . hollow piston in 26

30 . . . spring

32 . . . radially outward shoulder on 28

34 . . . radially inward shoulder in 26

36 . . . radial ports through 26

38 . . . annular float

40 . . . radial stop on 26

42 . . . radiation source

44 . . . radiation detector

46 . . . alarm circuit

48 . . . integral spout or neck

50 . . . screw-on closure

52 . . . central drain conduit

54 . . . hose fitting

56 . . . plurality of guide members

58 . . . slot between 56

60 . . . central frangible portion or pierceable septum portion

62 . . . plurality of guide members

64 . . . slot between 62

While our invention has been shown and described with reference toparticular embodiments thereof, those skilled in the art will understandthat other variations in form and detail may be made without departingfrom the scope and spirit of our invention.

Having thus described our invention in sufficient detail to enable thoseskilled in the art to make and use it, we claim as new and desire tosecure Letters Patent for:
 1. A photographic processor which receivesliquid from a container, comprising:a communication mechanism adapted tocommunicate with a spout which extends outwardly from the container, thespout having a central bore through which liquid can drain from a bottomof the container, to permit a flow of liquid downwardly from thecontainer to the processor; a radiation source which is adapted todirect a beam of radiation into the spout along a path intersected by afloat in the spout when the liquid drains to a preselected level withinthe spout; and a detecting device which is adapted to detect when thefloat intersects the beam, wherein the communication mechanism includesa probe which engages, and pushes upwardly, a piston within the spout topermit liquid to flow downwardly from the container.
 2. A processoraccording to claim 1, wherein a valve cylinder is provided within saidspout, such that a space which forms said central bore is definedbetween an outer peripheral surface of the valve cylinder and an innersurface of said spout, said float moving within said space and beingguided along the outer peripheral surface of said valve cylinder.
 3. Areplenishing device for replenishing processing liquid to a processorfrom a container which holds the processing liquid, the replenishingdevice comprises:a valve cylinder associated with a spout member of thecontainer; a central bore for connecting the container to the processor;a float slidable along a peripheral surface of the valve cylinder alonga direction of an axis of the valve cylinder between a first positionfor closing a radial port defined in the peripheral surface of the valvecylinder and a second position for opening the radial port; and a floatdetecting sensor disposed adjacent the radial port of the liquid feedingnozzle and capable of detecting the float at a detectable position.